Project Summary Injuries of mature central nervous system (CNS) axons result in loss of vital functions due to the failure of CNS axons regeneration. Neutralizing extracellular inhibitory molecules yields only limited regeneration or functional recovery in vivo, suggesting a critical role for neuron-intrinsic factors. As it has become apparent that the PTEN/mTOR pathway is critical for CNS axon regeneration, understanding the regrowth control of this pathway represents the first step toward developing novel therapeutic approaches to neural injury. Unfortunately, mTOR over-activity can result in tumor formation, metabolic diseases, and neurological disorders. It is therefore critically important to identify the specific downstream effectors by which PTEN/mTOR promotes axon regeneration, and to isolate them from other targets that mediate mTOR's deleterious effects. Using the anatomical and technical advantages of retinal ganglion cell and optic nerve as a CNS injury model, we have identified crucial regulators of axon growth, and are now ideally positioned to elucidate the downstream mechanisms by which PTEN/mTOR stimulates regeneration in mature CNS axons and identify translational targets of PTEN/mTOR govern adult CNS axon regeneration. These effectors are ideal therapeutic targets to promote regeneration in CNS injury and diseases, which can be selectively activated without activating other, potentially harmful pathways, thus to assist in safely translating our findings into novel neural repair treatments to preserve vital functions in patients with CNS injuries.